A huge boom reverberated around suburban Pittsburgh on New Year's Day, rattling homes and confusing residents. Community members and officials were were stumped. There was no seismic activity, no thunderstorm or any obvious signs of a detonation. On resident tweeted security footage of the boom. The National Weather Service confirmed that satellite data recorded a flash over Washington County shortly before 11:30 a.m., but agreed there was no thunderstorm or earthquake.